Considering what a provocative figure Errol Flynn was, “The Last of Robin Hood” sure is dull. Even the subversive tale of Flynn’s final love affair — with a 15-year-old girl in the late 1950s — isn’t enough to enliven the drama by co-writers and co-directors Richard Glatzer and Wash Westmore­land.

At least the casting is great. A mustachioed Kevin Kline — with a dandified accent and a habit of pantomimed swashbuckling — is a ringer for the 48-year-old Flynn, and Susan Sarandon transforms herself for the role of a deranged stage mother. She plays Florence Aadland, who has transferred her dreams of fame onto her daughter, Beverly (Dakota Fanning), an ethereal girl with middling talent who catches Flynn’s eye as she’s heading to her job as a chorus girl on a Hollywood movie set.

The moment is nicely shot, showing Beverly’s reflection in a window as she bounces down the street in her youthful way. A quick shift of focus shows that we’re not the only ones watching Beverly; Flynn is on the other side of the window, peering through the blinds.

She’s seduced by Flynn that evening during an “audition” at his house and is ultimately charmed into becoming his girlfriend. Her mother naively believes that Beverly is merely Flynn’s protégée, but even when Florence finds out the true nature of the pair’s relationship, she doesn’t really discourage the affair. Although Flynn is basically washed up, Florence thinks he could be the family’s savior.

In his defense, I suppose, Flynn believes Beverly is 18 when they first meet. That’s still three decades his junior, but at least it’s legal. And yet, true to his reputation as an insatiable lothario, uncovering her true age does not deter him. In one of the film’s few funny moments, Beverly’s father calls the actor “a walking penis.”

The movie briefly delves into a couple of charges of statutory rape lodged against the former Robin Hood in the early 1940s. (He was acquitted.) Even if Beverly had been aware of those charges, she might not have cared. She falls for Flynn, and in the process she becomes a pawn for both her mother and her lover. She makes the prematurely aged, vodka-pickled actor feel young and important while keeping alive Florence’s hopes of stardom for her daughter.

Beverly is a tragic figure, and Flynn and Florence aren’t the only ones who objectify her; Glatzer and Westmoreland do as well, painting her as a hollow character with no discernible personality. She mostly sits around looking wide-eyed. The fact that Flynn doesn’t really think of her as a person is bad enough — he calls her Woodsy, short for “wood nymph,” after deeming her an “exquisite creature.” That the filmmakers don’t bother to give her character any complexity only adds to the ick factor.

Ultimately the movie feels like an empty exercise. Sure, it’s a cautionary tale about the pitfalls of fame. But when the one figure most worthy of our sympathy is nothing more than a beautiful blonde robot, what’s the point?